Surface transfer doping of MoO₃on hydrogen terminated diamond with an Al₂O₃interfacial layer

A thin layer of Al2O3 was employed as an interfacial layer between surface conductive hydrogen-terminated (H-terminated) diamond and MoO3 to increase the distance between the hole accumulation layer in diamond and negatively charged states in the acceptor layer and, thus, reduce the Coulomb scattering and increase the hole mobility. The valence band offsets are found to be 2.7 and 3.1 eV for Al2O3/H-terminated diamond and MoO3/H-terminated diamond, respectively. Compared to the MoO3/H-terminated diamond structure, a higher hole mobility was achieved with Al2O3 inserted as an interface layer. This work provides a strategy to achieve increased hole mobility of surface conductive diamond by using optimal interlayer along with high high electron affinity surface acceptor materials.